Brake architecture for combined hydraulic and electromechanical braking system

1 . A vehicle braking system comprising:

a first hydraulic brake assembly associated with a first front wheel;

a second hydraulic brake assembly associated with a second front wheel;

a front electronic brake boost (EBB) module operably coupled to the first and second hydraulic brake assemblies to control primary operation of the first and second hydraulic brake assemblies;

a first electromechanical brake (EMB) assembly associated with a first rear wheel;

a second EMB assembly associated with a second rear wheel;

a controller operably coupled to the first and second EMB assemblies to control primary operation of the first and second EMB assemblies;

a first power network and a second power network providing redundant power supply to the vehicle braking system; and

a communication bus network operably coupling both the front EBB module and the controller to the first and second EMB assemblies to enable the front EBB module to provide control of backup operation of the first and second EMB assemblies responsive to the controller being inoperable,

wherein the communication bus network comprises a first bus network operably coupling the first and second EMB assemblies to the front EBB module, and a second bus network operably coupling the first and second EMB assemblies to the controller,

wherein the first bus network is a private controller area network (CAN) bus, and the second bus network is a public CAN bus, and

wherein the second bus network is separate and isolated from the first bus network.

2 . The vehicle braking system of claim 1 , wherein the first power network is operably coupled to the controller and the first EMB assembly, and the second power network is operably coupled to the front EBB module and the second EMB assembly.

3 . The vehicle braking system of claim 1 , wherein the first power network is QM power, and the second power network is ASIL B power.

4 . The vehicle braking system of claim 1 , wherein the first EMB assembly comprises a first electronic control unit (ECU) and the second EMB assembly comprises a second ECU,

wherein the first bus network extends between the first and second ECUs and the front EBB module, and

wherein the second bus network extends between the first and second ECUs and the controller.

5 . The vehicle braking system of claim 4 , wherein the first and second ECU are respectively operably coupled to a first wheel speed sensor and a second wheel speed sensor, the first wheel speed sensor providing wheel speed to the first ECU for the first rear wheel, and the second wheel speed sensor providing wheel speed to the second ECU for the second rear wheel, and

wherein in response to a loss of communication between the first and second ECUs and both the controller and the front EBB module, the first and second ECU apply a parking brake to the first and second rear wheels, respectively, when the first and second wheel speed sensors each indicate a zero wheel speed for the first and second rear wheels.

6 . The vehicle braking system of claim 5 , wherein the first and second ECUs provide a wheel end anti-lock brake system (ABS) function for the first and second rear wheels, respectively, in response to a loss of communication from the first and second wheel speed sensors.

7 . The vehicle braking system of claim 4 , wherein the first and second ECUs each include a respective motor to provide brake torque to the first and second rear wheels, respectively, and

wherein signaling for operation of the respective motor of the first and second ECUs is primarily provided via the controller via the second bus network, and is provided in backup via the front EBB module.

8 . The vehicle braking system of claim 1 , wherein a brake pedal of the system is operably coupled to the controller, and signaling for braking to the front EBB module is received from the brake pedal through the controller.

9 . A vehicle braking system comprising:

a first hydraulic brake assembly associated with a first front wheel,

a second hydraulic brake assembly associated with a second front wheel,

a front electronic brake boost (EBB) module operably coupled to the first and second hydraulic brake assemblies to control primary operation of the first and second hydraulic brake assemblies,

a first electromechanical brake (EMB) assembly associated with a first rear wheel,

a second EMB assembly associated with a second rear wheel,

a controller operably coupled to the first and second EMB assemblies to control primary operation of the first and second EMB assemblies,

a first power network and a second power network providing redundant power supply to the vehicle braking system,

a first bus network operably coupling the first and second EMB assemblies to the front EBB module, and

a second bus network operably coupling the first and second EMB assemblies to the controller,

wherein the first bus network and the second bus network operably couple both the front EBB module and the controller to the first and second EMB assemblies to enable the front EBB module to provide control of backup operation of the first and second EMB assemblies responsive to the controller being inoperable,

wherein the first EMB assembly comprises a first electronic control unit (ECU) and the second EMB assembly comprises a second ECU,

wherein the first bus network extends between the first and second ECUs and the front EBB module,

wherein the second bus network extends between the first and second ECUs and the controller,

wherein the first and second ECU are respectively operably coupled to a first wheel speed sensor and a second wheel speed sensor, the first wheel speed sensor providing wheel speed to the first ECU for the first rear wheel, and the second wheel speed sensor providing wheel speed to the second ECU for the second rear wheel, and

wherein in response to a loss of communication between the first and second ECUs and both the controller and the front EBB module, the first and second ECU apply a parking brake to the first and second rear wheels, respectively, when the first and second wheel speed sensors each indicate a zero wheel speed for the first and second rear wheels.

10 . The vehicle braking system of claim 9 , wherein the first power network is operably coupled to the controller and the first EMB assembly, and the second power network is operably coupled to the front EBB module and the second EMB assembly.

11 . The vehicle braking system of claim 10 , wherein the first communication bus is a private controller area network (CAN) bus, and the second bus network is a public CAN bus.

12 . The vehicle braking system of claim 11 , wherein the first power network is QM power, and the second power network is ASIL B power.

13 . The vehicle braking system of claim 9 , wherein the first and second ECUs provide a wheel end anti-lock brake system (ABS) function for the first and second rear wheels, respectively, in response to a loss of communication from the first and second wheel speed sensors.

14 . The vehicle braking system of claim 9 , wherein the first and second ECUs each include a respective motor to provide brake torque to the first and second rear wheels, respectively, and

wherein signaling for operation of the respective motor of the first and second ECUs is primarily provided via the controller via the second bus network, and is provided in backup via the front EBB module.

15 . The vehicle braking system of claim 9 , wherein a brake pedal of the vehicle braking system is operably coupled to the controller, and

wherein signaling for braking to the front EBB module is received from the brake pedal through the controller.

16 . A method for applying additional braking to the vehicle braking system comprising:

controlling primary operation of a first hydraulic brake assembly associated with a first front wheel and a second hydraulic brake assembly associated with a second front wheel via a front electronic brake boost (EBB) module operably coupled to the first hydraulic brake assembly and the second hydraulic brake assembly,

controlling primary operation of a first electromechanical brake (EMB) assembly associated with a first rear wheel and second EMB assembly associated with a second rear wheel via a controller operably coupled to the first EMB assembly and the second EMB assembly, and

providing redundant power supply to the vehicle braking system via a first power network and a second power network,

providing via a first wheel speed sensor a first rear wheel speed to a first electronic control unit (ECU) for the first rear wheel,

providing via a second wheel speed sensor a second rear wheel speed to a second ECU for the second rear wheel,

controlling backup operation of the first and second EMB assemblies via the front EBB module responsive to the controller being inoperable by a communication bus network operably coupling both the front EBB module and the controller to the first and second EMB assemblies, applying, in response to a loss of communication between the first and second ECUs and both the controller and the front EBB module, a parking brake to the first and second rear wheels, respectively via the first and second ECUs responsive to the first wheel speed sensor and the second wheel speed sensor each indicating a zero wheel speed for the first rear wheel speed and second rear wheel speed,

wherein the first and second ECUs are respectively operably coupled to the first wheel speed sensor and the second wheel speed sensor,

wherein a first bus network of the communication bus network operably couples the first and second EMB assemblies to the front EBB module and extends between the first and second ECUs and the front EBB module,

wherein a second bus network of the communication bus network operably couples the first and second EMB assemblies to the controller and extends between the first and second ECUs and the controller, and

wherein the first EMB assembly includes the first ECU and the second EMB assembly includes the second ECU.